who was the most powerful sith/jedi in episode 3

General Grevious
Obi-Wan
Anakin/Vader
Yoda
Sidious
Windu

general grevious was not jedi nor sith

ahhaha! im sorry, that order is extremely wrong...

yoda says specifically in the movie to obi wan "to fight this darth sidious, strong enough you are not."

so that immediately makes ur order wrong.

next grievous is not a jedi or sith, hes a cyborg who happens to use lightsabers.

the correct order is prolly something like:

Sidious
Yoda
Windu
Anakin
Obi-wan
Grievous

Windu

Definitely the Sith Lord

Palpatine allowed Windu and Anakin to think that he was beat, so that Anakin would betray Windu. Then he fried Windu.

He also knock Yoda off after a tough fight

Woah..woah...you're saying Windu is more powerful than Obi-Wan? I highly doubt that. This is what I say...

Sidious
Obi-Wan/Anakin tied
Yoda (he got whooped by Sidious, and he didn't show us too much skill against Dooku)
Windu
Dooku
Grievous

I believe, however, that if Anakin had fought Sidious, the Force would have protected him and he'd emerge the survivor, even if he would be so screwed up that he'd die because of injuries.

Windu is the category of combat power, that thats it